Publisher Summary This chapter illustrates examples based on a database of highway incident data. Information visualization displays can hold a limited number of data points, typically a few thousand, before they get crowded. One way to solve this problem with larger data sets is to create aggregates. Aggregations were used together with the Snap-Together Visualization (Snap) system to coordinate the visual displays of aggregates and their content. If two displays, each holding one thousand items, are used then rapid access and visibility can be maintained for a million points. This chapter focuses on using Snap for the drill-down coordination. This enables users to navigate from aggregates in one view to aggregate details in another view. This chapter also develops and analyzes different prototypes with different kinds of aggregates. It discusses challenges encountered in the development of the prototypes. The calculation of the aggregates is also a challenge, because it is unreasonable to calculate all the possible aggregates in advance and on-the-fly calculation may not always be practical.